In recent years, various torque transmission devices have been developed, and a torque transmission device capable of assisting an engine has been proposed as one of those devices (see PTL 1). For example, a motor generator is disposed in this type of torque transmission device. In the torque transmission device, the motor generator executes regeneration of extracting kinetic energy in travelling as electricity, whereas electricity stored in a battery is converted into rotation of the motor generator and the obtained rotation is inputted into a transmission.
In the torque transmission device, a hybrid drive device is mounted between the engine and the transmission. The hybrid drive device includes a multi-plate dry clutch, a motor generator and a pressing device configured to press the multi-plate dry clutch. In the hybrid drive device, the pressing device and the multi-plate dry clutch are disposed on the inner peripheral side of the motor generator while being aligned in the axial direction. With the arrangement, a clutch is turned on when the multi-plate dry clutch is pressed by the pressing device.